The phrase “cook the fish until it flakes easily with a fork” makes me cringe.
Julia Child tried to change it years ago. She said over and over again that if the fish flakes apart easily, it’s overcooked and dry. Besides not tasting as good, who wants to serve fillets that’ve been torn apart by a fork?
There is a way to know you’re fish is done without flaking off pieces or slicing it open and peeking inside. Yes, every species of fish is different. They vary in oil and water content, thickness of the fillets, and firmness of the flesh. But when it comes to telling when they’re perfectly cooked, the method is the same. All you need is a simple tool that’s probably already in your kitchen. 
This metal skewer is my favorite fish-testing tool. If you’ve got a cake tester, that’ll work. If the fillets are really thin, a toothpick will even do the trick. If you have to, you can use that damn fork, but please don’t tear apart your fish with it. 
Fish deserves your full attention. If you go make a salad or set the table while it’s cooking, you’ll probably overcook it. Since it cooks quickly, the difference is often only a minute or two.
To get a feel for this, at the beginning of cooking, gently slip the skewer into the center of the thickest part of the filet. Do you feel the resistance? I call that “hitting rubber.” That’s what the undercooked part feels like. Test again a minute later. You’ll notice the skewer goes through deeper the longer it cooks. When it’s done, it easily slips right through.
After you get a feel for it, you can just test toward the end when you know the fish is getting close. Visually, the fish will start to appear plump and springy. As soon as you don’t hit rubber in the fattest part of that fillet, take it off the heat and transfer the fish to a serving dish. 
Most fish will separate along the grain, but it should hold together nicely when you serve it. You know you’ve got it right when the flesh is opaque but still juicy. 
If all this is making you hungry, click FISH at the top menu, or scroll to the bottom of this page and search for the ingredients you’ve got on hand. Bon appétit!
Man just reading that made me go cook some fishes. Clever
Thanks, Uncle Freddie! Glad you cooked some fishes. I bet they were tasty.
I like that description of ‘hitting rubber’ – that’s just what undercooked fish feels like! Great tips on getting the fish just right — there’s nothing like perfectly cooked fish 🙂
Thanks, Nicole! I’m always trying to improve my fish-cooking skills. Looking forward to cooking with you one of these days!